News & Research

Natural Fiber Chairs

09/12/2012

Professor Seth Stem has designed these prototypes for BASF to demonstrate viable applications for a new material based on hemp.

Professor of Industrial Design Seth Stem stands beside a custom-made mold in the machine shop of Goodwin-Bradley Pattern Co., a 19th-century company tucked on a side street in South Providence. During its long history, Goodwin-Bradley has made parts for machines at the cutting edge of the technology of their time: Model Ts, Blackhawk helicopters, seals for the nuclear industry. Today, a diverse group of technicians, consultants and business leaders is here to see a promising new building material emerge from the press – a strong, lightweight and environmentally friendly alternative to plastic.

Stem is collaborating with BASF, the worldwide chemical company, to produce the seat and back of a large, handsome lounge chair designed to demonstrate the properties and possibilities of the material. He has designed the chair using a natural fiber composite of hemp and Acrodur®, BASF’s water-based acrylic resin. The material is unique in that it contains an unusually high proportion of natural fibers – 72% as opposed to the more typical 50% – and the binding agent is free of formaldehyde and other hazardous chemicals. When the fiber composite is heated and pressed into a form, it releases only steam in place of the volatile organic compounds (VOCs) and nauseous odors released by most commercial resins.

This, says Z. Ahmed Tahir, new business development manager at BASF, is good for the environment and a major benefit for manufacturers. In addition to obviating the issue of toxic emissions, the material is inexpensive and “it lets companies grow... In some parts of the country, you couldn’t get further permits to release more VOCs,” so manufacturing is limited. Using the fiber composite is a way of “pushing safer, more sustainable solutions into the market,” adds Beth Earnst, manager of employee and marketing communications for dispersions and pigments at BASF North America, who accompanied Tahir at the trial.

Sourced in the Netherlands, the hemp used in the composite has a 90-day growing cycle and is harvested by hand, according to Hugh McKee, president of the natural fibers importer Flaxcraft. That means it’s primarily human energy that's needed to harvest it every three months. Beyond carding, grading and cutting the fiber, it needs only to be dampened and impregnated with Acrodur® to be used by manufacturers. The composite also has a second life if it’s ground, recycled and remolded into a new product or filler.

For now Stem is focused on designing with the composite in its original incarnation. Before designing the chair, he initially created an exhibition piece – a box-like form – for BASF that demonstrated the structural properties and strength of the material, including its ability to sustain forms with sharp corners. He then moved on to design both the seat and back of the chair using one mold – a cost-effective move that allows for a beautiful, comfortable piece based on adjusting how the parts are arranged.

While new applications are still being developed, the hemp-Acrodur® composite can be used for roof linings and interior paneling in cars, as a molding wood binder for cork flooring and as a substitute for plastic in office furniture – including divider walls. Stem is excited about its design properties and would like to create at least one more piece of furniture using the material. During the two-day trial period Providence, he worked with Jeremy Funk, a technical specialist for BASF who, in addition to molding hemp-Acrodur®, also manufactured the first jute-Acrodur® and kenaf-Acrodur® chair backs and seats.

RISD alum Doug Stern84 ID, president of Fulcrum Product Development, helped in developing the first chair by machining the aluminum mold and helping to secure the necessary outsized equipment for the press. And Stem expects that as the research and design process progresses to possibly include dying the material or creating textiles to cover it, other RISD faculty and alumni are likely to become involved.

Professor Stem’s involvement is critical as BASF works to develop this new material, Tahir says. His work translates the composite from a mere resource to a viable product, proving its potential to the design community and the larger public. In other words, while BASF already understands the exceptional properties of this new material, Stem’s designs offer clear proof of its practical and aesthetic value.